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SMTP provider test email works but application emails not being sent



For a couple of weeks, the emails are not sent anymore.
I am using a custom smtp provider (, port: 587 ) with valid credentials. When I press “send test email”, the email is sent and I receive it. When I go to the email templates page and try to send emails from there, the email is not sent and I can see in the logs the following exception:
“error”: "Message failed: 554 5.2.0 STOREDRV.Submission.Exception:SendAsDeniedException.MapiExceptionSendAsDenied; Failed to process message due to a permanent exception with message Cannot submit message.
Also, the emails from the applications that is using the auth0 emails are not being sent.
I also tried to get the email templates using the api, and also the provider, all the details returned by the api are correct, the templates are enabled…Ca anyone help with this problem?


This looks like a problem with the SMTP server. Here’s a couple of links I found for the 554 error:

They talk about the clutter feature.



Thanks John.
I turned off clutter but it did not work :frowning: Anyway, I can send emails from that e-mail address from the backed of our application using the same configuration with smtp. The only problem is when trying to do it from auth0 integration…


HI Mirela,

I am not going to be much more help. I understand your tests - it works directly from your backend, but not from Auth0. The only thing I can say is that Auth0 is contacting the mail server, and the mailserver is replying with an error code. You will have to dig in to the mail server logs/settings to understand this error and figure out why it is being returned. I don’t know that mail server so I can’t help much. Sorry.